1 files changed, 10 insertions, 0 deletions
diff --git a/libavutil/display.c b/libavutil/display.c
index b2b98329a0..74aceb2847 100644
--- a/libavutil/display.c
+++ b/libavutil/display.c
@@ -63,3 +63,13 @@ void av_display_rotation_set(int32_t matrix[9], double angle)
     matrix[4] = CONV_DB(c);
     matrix[8] = 1 << 30;
 }
+
+void av_display_matrix_flip(int32_t matrix[9], int hflip, int vflip)
+{
+    int i;
+    const int flip[] = { 1 - 2 * (!!hflip), 1 - 2 * (!!vflip), 1 };
+
+    if (hflip || vflip)
+        for (i = 0; i < 9; i++)
+            matrix[i] *= flip[i % 3];
+}